The present invention is directed to a method and compositions for controlling aquatic pests, including zoological organisms and plants. More specifically, the invention is directed to a method and composition for controlling, inhibiting, and terminating populations of aquatic and marine pest plants, organisms, and animals in a target treatment zone. The invention is particularly applicable for sterilizing a treated water volume (whether or not enclosed) of mollusks, dinoflagellates, bacteria and algae.
The discovery in the Summer of 1988 of the Eurasian zebra mussel Dressiness polymorph in the Great Lakes of North America represents one of the most significant events in the history of aquatic biological invasion. However, this was not the first event of a non-indigenous species entering into U.S. water. Earlier, the spiny water flea Bythotrephes cedarstroemi and the ruffe Gymnocephalus cernuus had entered the United States from ballast water of European ports. It was soon discovered that zebra mussel had also entered the U.S. via ballast water of European origin.
Since the summer of 1988, there have been a number of aquatic species that have entered into the U.S. via ballast water taken from ports of other countries. It is estimated that several hundred organisms have been introduced into the U.S. via ballast water and/or other mechanisms, not limited to fisheries and ocean or coastal currents. As such, the integrity of the coastal waters of the United States and the Great Lakes basin has been substantially threatened by the increased rate of aquatic species introduction from other countries.
Prior to 1880, various methods for controlling ballast in ships were used. In fact, many streets in coastal towns are paved with stones once used for ship ballast. However, shortly before the turn of the century, water as ballast soon replaced these older methods of stabilizing ships. The rate of invasions by non-indigenous aquatic species rose dramatically since the turn of the century, with much of this being attributed to shipping. As transoceanic travel increased, so to has the inadvertent introduction of non-indigenous species that threaten natural waterways. This is a result of the diverse array of organisms that are able to survive the transoceanic travel in ship ballast water, sea chests, and on ship hulls. Of these, the ballast water of ships is one of the primary mechanisms by which organisms have invaded U.S. waters.
Ballast water consists of either fresh or salt water that is pumped into a vessel to help control its maneuverability as well as trim, stability, and buoyancy. The water used for ballast may be taken at various points during the voyage including the port of departure or destination. Container ships may make as many as 12 port visits/ballast exchanges during a single round-the-world journey. Any planktonic species or larvae that is near the ballast intake may be taken up and transported to the next port of destination. Globally, an estimated 10 billion tons of ballast water are transferred each year. Each ship may carry from a few hundred gallons (about 2 metric tons) to greater than 100,000 metric tons depending on the size and purpose. More than 640 tons of ballast water arrive in the coastal waters of the United States every hour.
The risk of invasion through ballast water has risen dramatically in the past 20 years as a result of larger vessels being used to transport greater amounts of material into and out of the U.S. It is estimated that between 3000-10,000 species of plants and animals are transported daily around the world. In regard to those materials being brought into the U.S., it is of interest to note that materials which contain animals, fruits, vegetables, etc., must be inspected by the U.S. Department of Agriculture in order to satisfy requirements that potentially harmful non-indigenous species are excluded. The irony is that the ship may be able to release ballast water that has been contaminated with a non-indigenous species. It is through this mechanism that several hundred species have been introduced into the United States.
The U.S. Fish and Wildlife Service currently estimates that the annual cost to the North American economy due to the introduction of non-indigenous species is more than $100 billion. While ballast water only accounts for a minor proportion of these introductions, the cost still runs to tens of billions of dollars in terms of industrial dislocation, clean-up, loss of product and loss of fisheries and other natural resources.
As noted above, one of the most notorious species introduced in the Great Lakes of North America is the Eurasian zebra mussel Dreissena polymorpha, which has become a major threat to inland water supplies from both a recreational and commercial aspect. Unfortunately, their range now extends from the Great Lakes to Louisiana and estimated economic losses are estimated at more than $4 billion for the calendar year 1999. This species is particularly prolific and a reproducing female can expel more than 40,000 fertile eggs per season which, upon hatching, may be found in colonies in excess of one hundred thousand per square meter. Furthermore, the colonies attach themselves to underwater structures that include, amongst others, water intake pipes, from which they can be readily disseminated into other environments, ship hulls, debris such as discarded automobile tires, sunken ships, and discarded metal drums. Established colonies often reach a thickness of 20 cm.
Of particular importance is the clogging of water intake pipes by zebra mussels that have a devastating industrial effect, especially in such uses as power plants, where there is a specific need for reliable water flow rates. Certain power plants have recorded a 50% water flow rate reduction following infestation and, in addition, zebra mussels appear to secrete substances, both in the living and dead state, that cause ferrous metal pipes to degrade. An associated problem also occurs in pipes that supply potable water because even following purification treatment, the water has an off flavor. This is attributed not only to the substances released by the living mussels, but especially by those that have died and are decaying. The latter most probably produce polyamines, such as cadaverine, which has a particularly obnoxious odor associated with decaying proteins and is most often noted in decaying meat.
Other detrimental environmental effects are the result of zebra mussel infestations both directly and indirectly. Of a direct nature are the effects on phytoplankton. Zebra mussels feed on phytoplankton, which are a source of food for fish, especially in lakes and ponds, thereby increasing the photosynthetic efficiency for other aquatic weed species because of increased clarity of the water. This has been shown to have dramatic effects on energy flow and food chains in some waters. Some fish species are threatened. The walleye, for example, thrives in cloudy water and it is generally believed by environmentalists that, increased water clarity resulted from zebra mussel activity will lead to the demise of that industry, presently estimated to be $900 million per year. Large-scale, multi-billion dollar degradations in native Great Lakes fisheries are already being felt as a result of competition from non-fishable species such as the Eurasian ruffe (Gymnocephalus cernuus) and the round goby (Proterorhinus marmoratus), which have been introduced through ballast water in the last two decades.
As a result of its feeding preferences, zebra mussels may radically alter the species composition of the algal community such that potentially harmful species may become abundant. An example is Microcystis, a blue-green alga of little nutritive value and capable of producing toxins which can cause gastrointestinal problems in humans. There are records of Microcystis blooms in Lake Erie and adjacent waterways. Toxic dinoflagellates such as Prorocentrum, Gymnodinium, Alexandrium and Gonyaulax often appear as blooms, sometimes known as xe2x80x9cred tidesxe2x80x9d, in many parts of the world. Apart from causing serious (sometimes fatal) ailments in several vertebrate consumers, including humans, several of these organisms have had devastating effects on shellfish industries in several countries and it is now accepted that ballast-water introductions were responsible in many of these cases.
Reports of the introduction of the cholera bacterium, Vibrio cholera, to the Gulf coast of the United States have now been traced to the importation of this species associated with planktonic copepod (crustacean) vectors in ballast water arriving at Gulf coast ports from South America. This, in turn, had been transported from Europe to South American ports by similar means.
As a result of the introduction of non-indigenous species into the United States, and in order to reduce the possibility of the introduction of other organisms in the future, in 1990 the U.S. Congress passed an act known as Public Law 101-646 xe2x80x9cThe Nonindigenous Aquatic Nuisance Prevention and Control Actxe2x80x9d under the xe2x80x9cNational Ballast Water Control Programxe2x80x9d which it mandates, among other things, studies in the control of the introduction of aquatic pests into the U.S. These control measures may include UV irradiation, filtration, altering water salinity, mechanical agitation, ultrasonic treatment, ozonation, thermal treatment, electrical treatment, oxygen deprivation, and chemical treatment as potential methods to control the introduction of aquatic pests. It is likely that other governments will pass similar legislation in the near future as the scope and costs of aquatic pest contamination become better understood.
Numerous methods and compositions have been proposed to control and inhibit the growth of various marine plants and animals. In particular, a number of compositions have been proposed to treat water and various surfaces having infestation of zebra mussels. Examples of various compositions are disclosed in U.S. Pat. Nos. 5,851,408, 5,160,047, 5,900,157 and 5,851,408. Treatment of various aquatic pests, other than toxic bacteria, is described in WO 00/56140 using juglone or analogs thereof.
These prior compositions and methods, although somewhat effective, have not been able to completely control the introduction of marine plants and animals into waterways. Accordingly there is a continuing need in the industry for the improved control of aquatic pests in the form of plants and animals, preferably aquatic flora, fauna, and other organisms that can be suspended in water and are susceptible to geographic migration by water intake, currents, or tides.
The present invention is directed to a method of controlling aquatic pests in the form of plants, animals, bacteria, or other microorganisms. The invention is particularly well suited for population control and sterilization of mollusks, dinoflagellates, toxic bacteria, and algae. One aspect of the invention is directed to a method and composition for treating water to sterilize the treated water of small and micro-sized aquatic pests including plants, animals, toxic bacteria, and microorganisms.
An object of the invention is to provide a method of treating water in a designated region of open water, an enclosed or a flow-restricted region to sterilize the area of aquatic pest microorganisms including plants, toxic bacteria, suspended animals, and other biologic organisms in sedimentary materials using at least one aquacidally active compound in an effective amount to be toxic to the target species.
A further object of the invention is to provide a method of treating ballast water in ships to control the transport of mollusks, dinoflagellates, toxic bacteria, algae and other microorganisms by treating the ballast water with an effective amount of an aquacidal compound to sterilize the ballast water.
Another object of the invention is to provide a method of treating water at an intake pipe of a process water system to sterilize the water of plants, animals and microorganisms.
A further object of the invention is to provide a method of treating ballast water to kill aquatic organisms found therein and to control their spread.
Still another object of the invention is to provide a method of treating a volume of water in an enclosed space or localized region of open water with a toxic amount of an aquacidal compound which is readily degraded to nontoxic by-products.
Another object of the invention to provide a method of inhibiting the spread of aquatic pests such as adult zebra mussels, zebra mussel larvae, oyster larvae, algal phytoplankton Isochrysis galbana, Neochloris, chlorella, toxic dinoflagellates (e.g. Prorocentrum), marine and freshwater protozoans and toxic bacteria (including vegetative cultures and encysted forms thereof), adult and larval copepods (vectors of Vibrio Cholera and Vibrio fischeri) and other planktonic crustaceans, e.g., Artemia salina, fish larvae and eggs by treating the water with an amount of at least one aquacidal compound of the type described herein in a quantity and for a sufficient period of time to kill the target aquatic pests.
A further object of the invention is to provide aquacidal compounds for the treatment of ballast water and water in other enclosed spaces, as biocidal additives to marine paints, and as agrochemicals for applying to plants for controlling snails and slugs.
Still another object of the invention is to provide a method of treating waste water from industrial and municipal sources to kill or control the spread of aquatic pest plant, animal and microorganisms.
These and other objects of the invention that will become apparent from the description herein are attained by method of inhibiting the growth of and preferably killing a population of a target pest microorganism by exposing said population to an effective amount of at least one aquacidal compound selected from the group consisting of: (a) quinones, (b) anthraquinones, (c) quinine, (d) warfarin, (e) coumarins, (f) amphotalide, (g) cyclohexadiene-1,4-dione, (h) phenidione, (i) pirdone, (j) sodium rhodizonate, (j) apirulosin, (k) thymoquinone, and (l) naphthalenediones which have the chemical structure of: 
wherein:
R1 is hydrogen, hydroxy or methyl group;
R2 is hydrogen, methyl, sodium bisulfate, chloro, acetonyl, 3-methyl-2-butenyl, hydroxy, or 2-oxypropyl group;
R3 is hydrogen, methyl, chloro, methoxy, or 3-methyl-2-butenyl group;
R4 is hydrogen or methoxy group;
R5 is hydrogen, hydroxy or methyl group;
R6 is hydrogen or hydroxy group.
The aquacidal compounds according to the present invention are surprisingly effective in controlling populations of aquatic pest organisms at very low concentrations. Typical target aquatic pests small and microorganisms that are translocated by movement of the surrounding water, e.g., currents, tides, and intake ports. When the aquacides of the invention allowed to remain in contact with the target pest organisms for a period within the range of several hours to several days, the target pest population is killed. The aquacidal compounds are then degraded through the effects of ultraviolet light, oxidation, hydrolysis, and other natural mechanisms into benign by-products that allow the treated water to be returned to beneficial use.
The present invention is generally directed to a method of treating water that hosts a target population of aquatic pests with an aquacidal agent for a sufficient period of exposure to reduce the target population in the treated water to benign levels or sterilize the treated water of the target population. The treated water can be located in a localized open water region, enclosed space or in a restricted flow path. Exemplary bodies of water that can be treated according to the invention include ship ballast water reservoirs, commercial process water taken in from a static or dynamic body of water, water ready to be discharged into a holding reservoir or waterway, cooling or other forms of holding ponds, intakes ports or pipes, discharge ports or pipes, heat exchangers, sewage treatment systems, food and beverage processing plants, pulp and paper mills, power plant intake and outlet pipes, cooling canals, water softening plants, sewage effluent, evaporative condensers, air wash water, canary and food processing water, brewery pasteurizing water, and the like. It is envisioned that the aquacidal agents of the present invention can also be used to treat shore areas or swimming regions if an aquatic pest population has reduced the recreational value of a region of water in a localized or localizable area in an otherwise open body of water.
In its preferred embodiments, the aquacidal agent made of one or more aquacidal compounds is added to ship ballast water at a concentration and for a period of exposure to the aquacidal compound that is effective in sterilizing the ballast water of target pests microorganisms. Such concentrations are typically sufficiently low to become diluted to a non-toxic level when discharged to a larger body of water so as to avoid or minimize harm to the indigenous species of plants and animals. Such a treatment method should help to prevent unintended migration of pest microorganisms between and among ports without significant capital expense or significant changes in commercial shipping practice.
The aquacidal compounds of the invention are mixed into the water using standard dispensing devices and dispensing methods as known in the art. The aquacidal compound can be dispensed as a single dose or over a period of time to maintain a desired concentration. Preferably, the aquacidal compound is introduced at a turbulent zone or other area where agitation will mix the aquacidal compound throughout the water to be treated. The aquacidal compound can be fed intermittently, continuously, or in one batch.
Target Pest Populations
Aquatic pest organisms and populations that can be controlled, killed, or otherwise rendered benign by the method of the invention are generally not free ranging between geographical regions of their own efforts but are subject primarily to the movement of the water currents or sediment around them. Such microorganisms move primarily under the influence of currents, tides, and ballast water taken in at one port and discharged at another. Aquatic pest microorganisms and populations that are targets for treatment according to the present invention include bacteria, viruses, protists, fungi, molds, aquatic pest plants, aquatic pest animals, parasites, pathogens, and symbionts of any of these organisms. A more specific list of aquatic pest organisms that can be treated according to the invention include, but are not limited to the following categories (which may overlap in some instances):
1) Holoplanktonic organisms such as phytoplankton (diatoms, dinoflagellates, blue-green algae, nanoplankton, and picoplankton) and zooplankton (jellyfish, comb jellies, hydrozoan, polychaete worms, rotifers, planktonic gastropods, snails, copedods, isopods, mysids, krill, arrow worms, and pelagic tunicates), and fish.
2) Meroplanktonic Organisms such as Phytoplankton (propagules of benthic plants) and Zooplankton (larvae of benthic invertebrates such as sponges, sea anemones, corals, mollusks, mussels, clams, oysters, and scallops).
3) Demersal organisms such as small crustaceans.
4) Tychoplanktonic organisms such as flatworms, polychaetes, insect larvae, mites and nematodes.
5) Benthic organisms such as leaches, insect larvae and adults.
6) Floating, Detached Biota such as sea grass, sea weed, and marsh plants.
7) Fish and shellfish diseases, pathogens, and parasites.
8) Bythotrephes cederstroemi (spiny water flea, spiny tailed water flea).
9) Macroinvertebrates, such as mollusks, crustaceans, sponges, annelids, bryozoans and tunicates. Examples of mollusks that can be effectively controlled are mussels, such as zebra mussels, clams, including asiatic clams, oysters and snails.
In further embodiments, the animals being treated are selected from the group consisting of bacteria, e.g., Vibrio spp. (V. Cholera and V. Fischeri), Cyanobacteria (blue-green algae), protozoans, e.g. Crytosporidiurn, Giardia, Naeglaria, algae, e.g., Pyrrophyta (dinoflagellates, e.g. Gymnodinium, Alexandrium, Pfiesteria, Gonyaulax Glenodinium (including encysted forms)), Cryptophyta, Chrysophyta, Porifera (sponges), Platyhelminthes (flat-worms, e.g., Trematoda, Cestoda, Turbellaria), Pseudocoelomates (e.g., Rotifers, Nematodes), Annelid worms (e.g., polychaetes, oligochates), Mollusks (e.g., Gastropods, such as polmonate snails), Bivalves, e.g., Crassostrea (oysters), Mytilus (blue mussels), Dreissena (zebra mussels), Crustaceans, larval-adult forms of copepods, ostracods, mysids, gammarids, larval forms of decapods, and Larval teleost fish.
The method of the invention in a first embodiment adds an effective amount of at least one marine plant and animal growth inhibiting compound to the water to be treated. The aquacidal compound is selected from the group consisting of a quinone, naphthalenedione, anthraquinone, and mixtures thereof. The quinones have the formula: 
where R1 is hydrogen, methyl, hydroxy or methoxy group;
R2 is hydrogen, hydroxy, methyl, methoxy or xe2x80x94NO2 group;
R3 is hydrogen, hydroxy, methyl or methoxy group; and
R4 is hydrogen, methyl, methoxy, hydroxy, or xe2x80x94NO2 group.
Examples of quinones found to be effective in controlling or inhibiting plant and animal growth in water include 1,4,benzoquinone (quinone), 2,5-dihydroxy 3,6-dinitro-p-benzoquinone (nitranilic acid), 2,6-dimethoxybenzoquinone, 3-hydroxy-2-methoxy-5-methyl-p-benzoquinone (fumagatin), 2-methylbenzoquinone (toluquinone), tetrahydroxy-p-benzoquinone (tetraquinone), 2,3-methoxy-5-methyl-1,4-benzoquinone, 2,3-methoxy-5-methyl-1,4-benzoquinone, and mixtures thereof. In further embodiments, the quinone can be an ubiquinone having the formula 
where n is an integer from 1 to 12. A particularly preferred ubiquinone has the formula above where n=10. In further embodiments, the ubiquinone has the above formula where n=6 to 10 and n is an integer.
In the embodiments where the marine plant and animal inhibiting composition is a naphthalenedione other than juglone, such naphthalenediones having the formula: 
wherein R1 is hydrogen, hydroxy or methyl group;
R2 is hydrogen, methyl, sodium bisulfate, chloro, acetonyl, 3-methyl-2-butenyl or 2-oxypropyl group;
R3 is hydrogen, methyl, chloro, methoxy, or 3-methyl-2-butenyl group;
R4 is hydrogen or methoxy group;
R5 is hydrogen, hydroxy or methyl group;
R6 is hydrogen or hydroxy group.
Examples of naphthalenediones include 1,4-naphthalenedione, 2-methyl-5-hydroxy-1,4-naphthalenedione (plumbagin), 2-methyl-1,4-naphthalenedione (Vitamin K3), 2-methyl-2 sodium metabisulfite-1,4-naphthalenedione, 6,8-dihydroxy benzoquinone, 2,7-dimethyl-1-4-naphthalenedione (chimaphilia), 2,3-dichloro-1,4-naphthalenedione (dichlorine), 3-acetonyl-5,8-dihydroxy-6-methoxy-1,4-naphthalenedione (javanicin), 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthalenedione (lapachol), pirdone, and 2-hydroxy-3-methyl-1,4-naphthalenedione (phthiocol).
The anthraquinones have the formula: 
wherein R1 is hydrogen, hydroxy or chloro;
R2 is hydrogen, methyl, chloro, hydroxy, carbonyl, or carboxyl group;
R3 is hydrogen or methyl group;
R4 is hydrogen;
R5 is hydrogen or hydroxyl group;
R6 and R7 are hydrogen; and
R8 is hydrogen or hydroxyl group.
Examples of anthraquinones that are suitable for treating water to control or inhibit marine plant and animal growth include 9,10 anthraquinone, 1,2-dihydroxyanthraquinone (alizarin), 3-methyl-1,8-dihydroxyanthraquinone, anthraquinone-2-carboxylic acid, 1-chloroanthraquinone, 2-methyl-anthraquinone, and 1-5 dihydroxyanthraquinone, 2-chloroanthraquinone.
Other compounds that can be used to control plant, animal, and microorganism growth either alone or in combination with each other and the quinones, naphthalenediones, and anthraquinones noted above include 9,10-dihydro-9-oxoanthracene (anthrone), 6xe2x80x2-methoxycinchonan-9-ol (quinine), 4-hydroxy-3-(3-oxo-1-phenyl butyl) -2H-1-benzopyran-2-one (warfarin), 2H-1-benzopyran-2-one (coumarin), 7-hydroxy-4-methylcoumarin, 4-hydroxy-6-methylcoumarin, 2[5-(4-aminophenoxy)pentyl]-1isoindole 1,3-(2H)-dione (amphotalide), sodium rhdixonate, 2-phenyl-1,3-indandione (phenindione), 2,5 dihydroxy-3-undecyl-2,5 cyclohexadiene, spirulosin and thymoquinone.
Compounds that are particularly effective in controlling macroinvertebrates include 2,3-methoxy-5-methyl-1,4-benzoquinone, 2-methyl-1,4-naphthalenedione, 2-methyl-5-hydroxy-1,4-naphthalenedione, 2-methyl -2-sodium metabisulfite-1,4-naphthalenedione, 3-methyl-1,8-dihydroxyanthraquinone, 2-methyl-anthraquinone, 1,2-dihydroxyanthraquinone, 1,4-naphthalenedione, and mixtures thereof. These compounds are also effective in controlling the growth of dinoflagellates.
In one embodiment of the invention, mollusks, dinoflagellates, toxic bacteria, and algae are treated to inhibit growth by applying an effective amount of compound selected from the group consisting of, 2,3-methoxy-5-methyl-1,4-benzoquinone, 2-methyl-1,4-naphthalenedione, and mixtures thereof.
One preferred embodiment of the invention is directed to a method of killing or inhibiting the growth of mollusks, dinoflagellates, toxic bacteria, and/or algae by exposing the mollusks, dinoflagellates, toxic bacteria, and/or algae to an effective amount of a quinone, anthraquinone, naphthalenedione, or mixture thereof. The method is effective in inhibiting the growth of toxic bacteria and musselsxe2x80x94particularly zebra mussels, and zebra mussel larvae, as well as other bivalvesxe2x80x94by applying the aquacide compound to the water in an effective amount. In a preferred embodiment, mussels, and particularly zebra mussels and zebra mussel larvae, are treated to kill or inhibit their growth by exposing the zebra mussels to a toxic amount of a molluskocide compound selected from the group consisting of 2,3-methoxy-5-methyl-1,4-benzoquinone, 2-methyl-5-hydroxy-1,4-naphthalenedione, 2-methyl-1,4-naphthalenedione, 2-methyl-2-sodium metabisulfite-1,4-naphthalenedione, 3-methyl-1,8-dihydroxyanthraquinone, 2-methylanthraquinone, and mixtures thereof.
In a further embodiment, these aquacidal compounds are incorporated as an active compound into a solid or liquid bait for agricultural use to kill or inhibit the growth of snails and slugs. The bait can be a standard bait as known in the art. In other embodiments, the aquacidal compound is formed into a solution or dispersion and applied directly to the plant in an effective amount to treat the plant for controlling snails and slugs.
Aquacidal Amount
The amount of the aquacidal ingredient to be added will depend, in part, on the particular compound and the species of plant or animal being treated. As used herein, the term xe2x80x9ceffective amountxe2x80x9d or xe2x80x9caquacidalxe2x80x9d refers to an amount that is able to kill the target species or render the target specie population inert and otherwise not viable of sustained vitality.
The method for treating water to kill a target plant or animal introduces the aquacidal compound to the water in the amount of less than 1 wt %. Preferably, the aquacidal compound is added in an amount within the range of about 100 ppb to about 500 ppm (parts per million), more preferably in an amount within the range from about 500 ppb to about 300 ppm, most preferably within the range of 500 ppb to 250 ppm, and especially in an amount within the range of 1 ppm to about 250 ppm. Generally, the amount of the aquacidal compound used in treatment of ballast tank water will range from about 1 ppm to about 200 ppm.
The target pest population should be exposed to the aquacide at the selected concentration for a time sufficient to kill the target population. Exposure periods sufficient are generally within the range of a at least one hour to a period of less than 96 hours (4 days) for both fresh water as well as salt water. A preferred exposure is within the range from about two hours to about 48 hours. Routine sampling and testing can be used to determine precise concentrations and exposure durations for a specific aquacidal compound, water type, target population, method of introduction, and temperature.
Coatings
The aquacidal compounds of the invention can also be added to paints and coatings in a concentration sufficient to provide population control without adversely affecting the efficacy of the coating. The paint or coating composition can be applied to a surface, such as the hull of a boat, intake pipes, ship chests, anchors, and other underwater structures to prevent the plants and animals from growing and adhering to the surface.
The paint or coating composition can be conventional marine paint containing various polymers or polymer-forming components. Examples of suitable components including acrylic esters, such as ethyl acrylate and butyl acrylate, and methacrylic esters, such as methyl methacrylate and ethyl methacrylate. Other suitable components include 2-hydroxyethyl methacrylate and dimethylaminoethyl methacrylate that can be copolymerized with another vinyl monomer, such as styrene. The paint contains an effective amount of at least one aquacidal compound to inhibit plant an animal growth on a painted substrate. In embodiments of the invention, the aquacidal compound is included in an amount to provide a concentration of the aquacidal compound at the surface of the coating of at least 500 ppb, preferably about 1 ppm to 50 wt %, and more preferably within the range of 100-500 ppm to provide a plant and animal controlling amount of the aquacide compound in the coating.